1. Field of the Disclosure
The present disclosure relates to an internal combustion engine having multiple balance shafts.
2. Related Art
Balance shafts have been used for controlling unwanted vibrations associated with internal combustion engines for many years. In some engines, dual balance shafts are used, with the balance shafts being driven at twice the rotational speed of the crankshaft. In an often used formula, a first balance shaft will be driven directly by the engine's crankshaft, via a chain or belt, with a second balance shaft being driven in the opposite rotational direction by a set of gears, with one gear being applied to each of the two balance shafts. Unfortunately, because of crankshaft rotational speed variations which are inherent with any reciprocating combustion engine, the balance shafts will tend to be accelerated and decelerated as the crankshaft accelerates and decelerates, with the result being that noise is generated by the meshing gears extending between the balance shafts.
It would be desirable to provide a system for preventing unwanted gear lash noise arising from a balance shaft system, at a reasonable cost and without adding additional parts to an engine.